Hunting Washington Forum
Equipment & Gear => Scopes and Optics => Topic started by: Special T on March 23, 2011, 01:06:16 PM
-
So I just got back from a prairie dog shoot near Burns OR, and my bro in law and cousin both have the Nikon coyote special on top of identical R15 shooting 223. How big a steel circle do i need to make for our long range practice out at the bro in laws farm? I think he has an 8" steel that is close but its too thin and blow though it closer than 300yrd... I have a 12" 1.5 in thick circle but want to know if i need a larger one or need to trim it down? I tried looking for info n the Nikon site and her and came up with nothing.. Thanks!
-
this is what i found off the nikon sight. im not sure what unit of measure they use to measure the crosshair wire, but having a couple BDC recticles myself i really want to say they used mm in the pic.
hopefully once you figure out what units they use someone with better math skills than i can help extrapolate how big of a plate you need for each ring, also notice they only give the circle dia. on the 9 power
-
thanks that's a start!
-
do a google search on first focal plane and it will help explain it
-
Depends on the magnificaion setting of the scope. The size of the reticle circles stays the same, but the size of the target varies according to the magnification setting.
-
I bring up this old thread because im continuing to do research on this scope. I contacted Nikon and they sent me in PDF form the 2016 SRO Catalog. In it it has all the pertinent information regarding their retacales. T image Upland posted is the measurements in inches at 100 yards on 9 power. They are also the same numbers for the 4.5x14 @ 100 yards at full power. Since this seems to be a MOA measurement system then all the same rules would apply correct?
Is there a mathematical way to calculate what the sizes would be on 3 power? I keep putting a few pieces of the pie together and eventually ill have it figured out!
-
Wouldn't the circle cover 3X the area that it does at 9X? The target will be smaller at lower magnification.
So, let's say a 9" circle is covered at 9 power, change it to 3X and it would cover a 27" circle.
-
Ive done some informal measuring. @ 100 yards i believe the Big Circle "C" is 8" on 3 power 5" & 2" for the smaller circles. This is just some rough measurements that i did from a bench with sand bags to steady the scope... I believe there is at least 1" error possible.
-
tag
-
I have scope that changes retical size but not drop so I understand the difference. If I cannot find some way to do the math ill just continue to do it the hard way with known shapes and sizes intil I build a dope card.
-
If the su tensions are on 9 power they may not be exactly tripled on 3 power. Do you have Nikon spot on app on your smart phone? That will handle all the math for you and you can mess with it. Other than that I would spend some time at 95-96 yards with a gun vice or led sled and 1 inch graph paper. 1 moa equals 1 inch somehwere between 95 and 96 yards. Play with it at all powers and figure out the size in moa of the circles and wrote it down, also spacing of the circles in moa.
-
Excellent question and I can say in 6 years it is the first time I have heard it. The coyote special scope is not made for target shooting but for getting on fur and making the shot. One of my favorite scopes for fast target acquisition. The sub-tension's listed in the earier thread are indeed for 9X magnification. Unfortunately I'm not sure what they woould change to at lower magnification using the second focal plance scope. I will try to find out the answer and get back to you. That being said, it would be easy to make steel target's to fit what we know to be true with the 9X subtension's.Even at 100 yards most folks are going to use max magnification and getting used to getting on target and sending a round might be more productive then filling the circle with metal. Spot On will show you the differences in distance if you turn turn your scope to a lower magnification as I am showing below.
(https://hunting-washington.com/smf/proxy.php?request=http%3A%2F%2Fi1216.photobucket.com%2Falbums%2Fdd363%2Fbman940%2FScreen%2520Shot%25202016-04-12%2520at%25202.39.42%2520PM.png&hash=a4d254193f6b609d2906ac2340dc9f1cd5f5b259)
-
I seem to toss up on moving coyotes on 3 power because of the eye relief. The size of the circle does in fact change at 3 power. Ive written my estimations down and will continue to do so. Im mostly thinking of the quicker offhand shots and figured there had to be some way to figure it out mathematically instead of the thumb nail sketch. I have played with the spot on site and love it for the drop, so there has to be a way to do the same thing with the change in circle size.
-
It is 3X more. Example, The subtension's triple at 3 x over the stated MOA at 9X. 1 MOA at 9X becomes 3MOA at 3X, add 300 yards to that and the subtension of the circle cover's 9 inches. I'f you want to make steel target's I'd go with 12 inch steel plates and practice getting on them quickly. I hope this helps out?
-
It is 3X more. Example, The subtension's triple at 3 x over the stated MOA at 9X. 1 MOA at 9X becomes 3MOA at 3X, add 300 yards to that and the subtension of the circle cover's 9 inches. I'f you want to make steel target's I'd go with 12 inch steel plates and practice getting on them quickly. I hope this helps out?
So id the main circle is 3" @9power then it should be 9"@3power by your math.this is fairly close to my observed 8"
-
Correct. Strange no one had ever asked me that question before, so I wanted to make sure I had te correct answer to pass on. Now if you have a first Focal plance scope you don't have to worry about any of this.
Thanks for the question.
-
I have an older Prostaff 4-12x40 BDC. since I am saving up money for a new scope on my 338LM, I am going to use this scope in the interim while I save up.
I put together this little quick reference sheet for when using it at extended ranges.
The click values for Nikon scopes are IPHY, and so is the reticle. The reticle is based off of a 100 yard zero and at max magnification.
The mill and MOA holds need to be ratioed with respect to magnification.
What this means is at 4 power, the bottom post (dimension I) would be 42.9MOA.
in mathematical terms: (Hold in MOA)x(12/4)
it also works for the Mill holds also
-
here is the Coyote Reticle
-
Woodlandshooter. Great info there. I would love the math to be incorperated into the spot on web site so that you could make a quick cheet sheet for your specific combination.
-
I also have the Spot On app in my I-Phone.
yesterday I verified that the NIKON is indeed in IPHY, and not MOA by matching environmental conditions between the App and also my "old standby" Pesja Ballistics spreadsheet.
To convert from IPHY to MOA, at 100 yards, divide the IPHY value by 1.047.
To convert from IPHY to Mils at 100 yards, divide the IPHY value by 3.6.
if you are using another ballistics program other than Spot On, you will need to remember that click values on the Nikon Scopes are IPHY. You will need to make the correction at extended ranges if you are "dialing" because, if you don't, you will miss the target.
-
This is the kind of great info I wish they had posted there.
-
well, the "intent " of these scopes are general hunting use...not long range precision, so they don't publish that kind of info.
I checked the turret travel on my Prostaff, and it's ~65 IPHY for the elevation turret.
With a 20 MOA base, it could get me to 1600 yards at 12x...if I include the reticle. might get out to test that theory this weekend.
-
Even tho these scopes are not made for long range shooting we can define long range somewhere in the 4-600yard range for a 223. Since the circles purpose are different sizes it would be helpful in offhand target ranging. Since this scope is mostly predator/coyote emphesized some rough gauges would be perfect. Perhaps I am the only one but a perfect shot is less portant to me on a coyote than on a deer or elk.
-
I've got a 4 1/2-14 Buckmaster on a rifle. It has the BDC reticule, I hate it! Figured I could get it, great price, and then have Nikon change it out, they don't do that. On my 243 I have taped to the stock a paper with the drop at different range's. That aand my range finder work very well. The 243 has the 3-0 Buckmaster with duplex reticule.
